Audio processing devices generally include one or more microphones to sense sounds from the environment and produce corresponding audio signals. An active noise cancellation (ANC) headphone, for example, includes a reference microphone to generate an anti-noise signal that is approximately equal in magnitude, but opposite in phase, to the sensed ambient noise. The ambient noise and the anti-noise signal cancel each other acoustically, allowing the user to hear a desired audio signal.
Conventional ANC systems (and other noise reduction or cancellation systems) do not, however, completely cancel all noise, leaving residual noise and/or generating audible artefacts that may be distracting to the user. For example, unlike ambient sounds cancelled in an ANC system, wind noise may occur at the microphone in response to local air turbulence at the microphone components. Wind noise may not be correlated to the ambient noise that reaches the user's ear canal, and the corresponding anti-noise signal may be audible to the user. Noise suppression systems that attempt to remove background noise from an audio signal face similar challenges in removing wind noise.
In view of the foregoing, there is a continued need for improved noise reduction and noise cancellation systems and methods for audio signals that may include sensed wind noise. There is also a continued need for improved active noise cancellation systems and methods for headphones, earbuds and other personal listening devices that may operate in windy environments.